The cleavage of ethers with organic acids has been known since the 1890's, for example dihydroxy maleic acid was employed in the presence of dry hydrogen bromide to cleave ethyl ether and form the diethyl ester of the acid. Oxalic, acetic, benzoic, stearic and boric acids were employed later in analogous reactions [J. Chem. Soc. 73, 554 (1898)]. Ethyl acetate and tertiary butyl alcohol were formed by cleaving tertiary butyl ethyl ether with acetic acid in the presence of a trace of sulfuric acid. This was reported as a special case because of the exceptionally high reactivity of the tertiary butyl radical [J. Am. Chem. Soc. 54, 2099 (1932)]. A year later Hennion, et al. reported the reaction of several ethers with various organic acids in the presence of boron trifloride to form esters. A more recent reference Die Makromolekulare Chemie, Vol. 54, 1962, p. 15) to a cleavage of glycols containing alkyl end groups, e.g. diethylene glycol diethyl ether, was found in which acetic anhydride was employed in the presence of boron trifluoride to produce a good yield of ethylene glycol diacetate.
While the cleavage of ethers on a laboratory scale and under certain specialized conditions appears possible, the conversions, yields, reactants or catalyst systems employed have not been conducive to the development of a commercially acceptable process. Either conversions or yields, or both have been inadequate, or the catalyst systems and reactants employed have been exotic and expensive. Thus, the cleavage of polyglycols and polyglycerine, by the present process provides a successful method suitable for commercial development.
In processes employed commercially to make glycols and glycerine there are appreciable amounts of higher polymeric etherlinked polyols formed. Although there are some limited uses for the polyglycols and polyglycerine, it would be highly desirable if these could be converted to the more useful monomeric glycols and glycerine. The present process provides just such a desired result.